 
 (defn vec-to-elem [v]
   (assert (pos? (count v)) (hiccup-err v "Hiccup form should not be empty"))
-  (let [tag (nth v 0)]
+  (let [tag (nth v 0 nil)]
     (assert (valid-tag? tag) (hiccup-err v "Invalid Hiccup form"))
     (cond
       (hiccup-tag? tag)

    0 (.' util/react createElement comp jsprops)

    1 (.' util/react createElement comp jsprops
          (as-element (nth argv first-child)))

    (.apply (.' util/react :createElement) nil
            (reduce-kv (fn [a k v]

            pos (.indexOf n ">")]
        (case pos
          -1 (native-element (cached-parse n) v 1)
          0 (let [comp (nth v 1 nil)]
              ;; Support [:> comp ...]
              (assert (= ">" n) (hiccup-err v "Invalid Hiccup tag"))
              (assert (or (string? comp) (fn? comp))
